diff --git a/geeksville-private/bl602.md b/geeksville-private/bl602.md
index f4c27500c..6f42f4c66 100644
--- a/geeksville-private/bl602.md
+++ b/geeksville-private/bl602.md
@@ -20,4 +20,6 @@ make
 
 * todo run hello world on hardware (check for bl604 vs bl602 first)
 * build/run in the crummy arduino environment
-* build in platformio
\ No newline at end of file
+* build in platformio
+
+https://lupyuen.github.io/articles/lorawan2